M5.1 earthquake 34 km N of Cauquenes, Chile

Thursday, July 1, 2010, 20:58:22 UTC · 35.655°S, 72.360°W

A magnitude 5.1 earthquake struck 34 km N of Cauquenes, Chile on Thursday, July 1, 2010, 20:58:22 UTC, at a depth of 24.4 km (shallow). USGS received 22 “Did You Feel It?” reports, with a maximum reported intensity of VI (strong). It is the strongest earthquake within 300 km since an M5.5 on June 29, 2010.

Magnitude: 5.1; Moderate · mb
Depth: 24 km; Shallow
Felt reports: 22; Max intensity VI
Est. shaking: —; No ShakeMap
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 75 km aftershock search area

In context

How big was it, and why here?

Energy released

674 tons of TNT

That is about 1/22 of the Hiroshima bomb. It released about 1 times the energy of a magnitude 5.0.

Tectonic setting

137 km

from the nearest mapped plate boundary, between the Nazca and South American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

24 km

Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.

Did You Feel It?

Where it was felt

Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.

Place	Intensity	Reports	Distance
Santiago, Metropolitana, Chile	II · Weak	9	291 km
Talca, Maule, Chile	IV · Light	5	72 km
Curicó, Maule, Chile	IV · Light	3	128 km
Cauquenes, Maule, Chile	VI · Strong	1	41 km
Linares, Maule, Chile	IV · Light	1	76 km
Angol, Araucanía, Chile	IV · Light	1	240 km
Concepción, Bío Bío, Chile	II · Weak	1	146 km
Rancagua, Libertador General Bernardo OʿHiggins, Chile	II · Weak	1	222 km

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.

After the main event

Aftershocks within 75 km

USGS lists 5 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.0 on July 6, 2010. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 617 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 38 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 37,515 recorded deaths. The most severe:

1939M8.3
Chillan
25 Jan 1939 · 67 km away · intensity X
30,000 deaths$920 million damagetsunami
1906M8.2
South Central
17 Aug 1906 · 297 km away · intensity XI
4,000 deaths$100 million damagetsunami
1960M9.5
Puerto Montt, Valdivia
22 May 1960 · 292 km away · intensity XII
2,226 deaths$1.0 billion damagetsunami
2010M8.8
Maule, Concepcion, Talcahuano
27 Feb 2010 · 71 km away · intensity IX
558 deaths$30 billion damagetsunami
1928M7.6
Talca, Chillan, Santiago, San Fernando
1 Dec 1928 · 80 km away · intensity IX
279 deathsSevere damage ($5–24M)tsunami
1985M8.0
Central Coast, San Antonio, Valparaiso
3 Mar 1985 · 287 km away · intensity VIII
180 deaths$1.5 billion damagetsunami

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers